The radio host also reveals which guest "went running out of the studio ... because I was insane."
With the release of his new book, "Howard Stern Comes Again," the radio host has been very forthcoming when it comes to regrets from the shock-jock interview style of his earlier days. But not everybody has been as receptive when it comes to his apologies.
Speaking with Rolling Stone, Howard Stern explained that one of his guests -- who will remain nameless -- didn't want to hear it.
"I don't want to say who, out of respect to that person. Listen, it's not like I'm an alcoholic who made calls to everybody in my life. But I did call certain people. Most were very gracious and said, 'I'm glad you made this call,'" he explained. "And this one person — I don't think they were wrong — said to me, 'You know what? You caused me a lot of pain and grief. I don't know that I can really get over this.'"
His response: "I'm not looking for you to get over it. I'm not looking for anything other than letting you know I was a dick and I'm a fan of yours. And I'm sorry I caused you so much grief."
Stern also hoped to say he was sorry to Robin Williams for how he treated the comedy great during his appearance. Sadly, Williams took his own life before that happened.
"I was a baby. I want every listener. I want everyone focused on me. You're not going to be funnier than me. You're not going to come into my studio and steal the moment from me,'" he recalled of his behavior during Williams' interview. "This is who I was. Rather than say to Robin Williams, 'My God, you're here,' and celebrate an amazing talent and the beauty of that guy's career, he walks in and I start in, 'Hey, you're f--king your nanny.' Bam, sledgehammer. Sock him right in the f--king head. Asshole. Me, not him."
"I had this idea that I gotta call him and apologize. I started to put it in process and see if he would take my call, but he killed himself," added Stern. "I get chills when I tell you."
Stern also expressed regret over his interviews with both George Michael and "SNL" superstar Gilda Radner during his convo with Rolling Stone, while referring to his old interview style.
"When George Michael was in Wham!, I said to him first thing, 'Are you gay?' OK. Yes, that's outrageous, and it's not fair to the guy," he said. "Gilda Radner, she went running out of the studio and banged her head on a speaker because she was so freaked out by me because I was insane. I was f--king crazy because I was so worried that the audience would tune out."